Mycetoma: comparison of MR imaging with CT.

Magnetic resonance (MR) images obtained in 18 patients with pathologically confirmed mycetoma in the body (n = 4) or lower extremity (n = 14) were retrospectively reviewed and compared with computed tomographic (CT) scans in 15 patients and surgical findings in 10. T1-weighted images showed an infiltrating mass (same signal intensity as muscle) involving skin, subcutaneous fat, muscles, tendons, and other tissues. On T2-weighted images, the mass and affected structures showed moderately increased signal intensity. Bone marrow involvement was detected in seven patients and was best visualized on T1-weighted images. CT showed moderate enhancement of the infiltrative process in all patients. Bone changes, seen in nine, included coarse trabeculation, periosteal reaction, endosteal proliferation, and patchy destruction. MR imaging and CT were comparable and correlated well with surgery in showing the extent of soft-tissue involvement. Early bone changes (important for therapy planning for pedal mycetoma) were seen only at CT. The study showed that MR imaging is sensitive for assessing the extent of mycetoma in the soft tissues. CT should be the method of choice for staging pedal lesions because it can be used to detect early bone involvement.

MR imaging of thoracic and abdominal wall infections: comparison with other imaging procedures.

Infections of the chest and abdominal wall are rare but potentially fatal disorders that can occur spontaneously or in association with diabetes mellitus, immunosuppression, or trauma. The condition (either in the form of necrotizing fasciitis and/or pyomyositis) is difficult to diagnose clinically because of poor localizing signs. Prognosis depends on early recognition, extent of disease, and type of causative organism. Pathologically, the infections can manifest as cellulitis, abscess, and/or granulation tissue formation. To determine the value of MR imaging in the assessment of these infections, we compared the findings of MR with those of CT, sonography, scintigraphy, and plain radiography in 13 patients with proved thoracic and/or abdominal wall infection. The imaging findings were correlated with microbiological, pathologic, and/or surgical data. The isolated pathogens were Staphylococcus aureus (n = 6), Klebsiella pneumoniae (n = 1), Mycobacterium tuberculosis (n = 4), and Streptomyces somaliensis (n = 2). In 10 of 13 patients, MR imaging and CT were comparable and proved accurate in detecting the nature and extent of the inflammatory process. In seven of the patients, CT also was useful in guiding percutaneous biopsy and/or partial drainage procedures. Coronal and sagittal MR images were helpful for planning surgery. Rib osteomyelitis was missed with both techniques in one patient; in two other patients who did not have CT, MR imaging missed osteomyelitis of the ribs, the spinous process of a vertebral body, and the iliac bone. Sonography underestimated the extent of the disease in all 13 patients, but detected fluid collections in six. Findings on scintigraphy and plain radiography were the least contributory to the diagnosis and treatment of these patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Brucellar and tuberculous spondylitis: comparative imaging features.

Radiographs, scintigrams, computed tomographic scans, and magnetic resonance (MR) images of 17 patients with brucellar spondylitis and 15 with tuberculous spondylitis were analyzed to identify distinguishing features. Characteristic findings of brucellar spondylitis included predilection for the lower lumbar spine (68% of lesions), bone destruction limited to the end plates, disk collapse (16 of 19 disks), and granulation tissue or localized soft-tissue edema (17 of 19 sites). MR imaging showed diffuse increased signal in vertebrae and disks on long repetition time (TR)/echo time (TE) images in four patients and focal increased signal with normal disks in one. Epidural extension was best seen on short TR/TE images in four. Tuberculous spondylitis was characterized by predilection for the midthoracic spine (73%), vertebral destruction with gibbus deformity (60%), disk collapse, and paraspinal abscesses (14 of 15). On MR images signal intensity of affected vertebrae was similar to but more severe than findings in patients with brucellar spondylitis. Scintigraphy was the least helpful in differentiating the two infections. Lesions of tuberculous spondylitis affecting the lower lumbar spine were difficult to differentiate from those of brucellar spondylitis.